Bed bugs are small nocturnal insects of the family Cimicidae that feed off the blood of humans and other warm blooded hosts. Bed bugs exhibit cryptic behavior, which makes their detection and control difficult and time consuming. This is particularly true for the common bed bug, Cimex lectularius, which has become well adapted to human environments. Other species of bed bugs are nuisances to people and/or animals as well.
While bed bugs have been controlled in many areas, such as the United States, the increase in international travel has contributed to a resurgence of these pests in recent years. There are many aspects of bed bugs which make it difficult to eradicate them once they have established a presence in a location. Accordingly, there is a need for effective traps to determine the presence of bed bugs before they become entrenched.
Adult bed bugs are about 6 millimeters long, 5 to 6 millimeters wide, and are reddish brown with oval, flattened bodies. The immature nymphs are similar in appearance to the adults, but are smaller and lighter in color. Bed bugs do not fly, but can move quickly over surfaces. Female bed bugs lay their eggs in secluded areas and can deposit up to five eggs per day, and as many as 500 during a lifetime. The bed bug eggs are very small, about the size of a dust spec. When first laid, the eggs are sticky causing them to adhere to surfaces.
Bed bugs can go for long periods of time without feeding. Nymphs can survive for weeks without feeding, while adults can survive for months. Consequently, infestations cannot be eliminated simply by leaving a location unoccupied for brief periods of time. Further, such feeding habits make it difficult to monitor whether bed bugs are present as they may only be attracted to bait when hungry. Thus, in order to be effective, a bed bug capturing device must be able to generate attractants at an effective concentration for an extended period of time.
While bed bugs are active during the nighttime, during daylight they tend to hide in tiny crevices or cracks. Bed bugs may therefore find easy hiding places in beds, bed frames, furniture, along baseboards, in carpeting and countless other places. Bed bugs tend to congregate but do not build nests like some other insects.
Bed bugs obtain their sustenance by drawing blood through elongated mouth parts. They may feed on a human for 3 to 10 minutes, although the person is not likely to feel the bite. After the bite, the victim often experiences an itchy welt or a delayed hypersensitivity reaction resulting in a swelling in the area of the bite. However, some people do not have any reaction or only a very small reaction to a bed bug bite. Bed bug bites have symptoms that are similar to other pests, such as mosquitoes and ticks. It is not possible to determine whether a bite is from a bed bug or another type of pest; and bites may be misdiagnosed as hives or a skin rash. Consequently, bed bug infestations may frequently go on for long periods before they are recognized.
Bed bug infestations originate by a bed bug being carried into a new area. Bed bugs are able to cling to possessions and hide in small spaces, such that they may be transported in a traveler's belongings. As a result, buildings where the turnover of occupants is high, such as hotels, motels, inns, barracks, cruise ships, shelters, nursing homes, camp dwellings, dormitories, condominiums and apartments, are especially vulnerable to bed bug infestations.
Because of all the features of bed bugs described herein, bed bugs are both difficult to detect and eradicate. Professional pest removal specialists and pesticides are needed. It is necessary to remove all clutter and unnecessary objects from a room, remove bed bugs and eggs as much as possible through vacuuming, and apply pesticides to likely hiding areas. This type of treatment for eradication can be disruptive to a business such as a hotel. As a result, it is desirable to detect bed bugs at the earliest possible moment before an infestation becomes established.
The tiny, mobile and secretive behavior of bed bugs makes it nearly impossible to prevent and control an infestation unless they are quickly discovered and treated. Bed bugs have been found to move through holes in walls, ceilings and floors into adjacent rooms. Devices and methods for the early detection of bed bugs are especially needed in the hospitality industries.
Many attempts have been made to devise bed bug monitoring and/or capture devices in the past. Several of these devices employ pheromones, human sweat components or other organic chemicals which are heavier than air as lures in order to attract bed bugs to their trapping mechanism.
Thus, U.S. Patent Application 2008/0168703 A1 discloses a chemical formulation which is capable of attracting bed bugs when volatized comprising a mixture of chemicals found in bedbug pheromones including a monoterpene, a saturated aldehyde, an unsaturated aldehydes and a ketone.
Somewhat similarly, U.S. Patent Application 2007/0044372 discloses components of breath, perspiration and hair or skin oil which may be employed as bed bug olfactory attractants.
However, devices employing such heavier than air organic chemical attractants have, in general, not proven to be commercially effective. The present inventors have studied many aspects of bed bug behavior, and believe that one factor in the failure of such devices to desirably perform is the failure of such devices to disperse such attractants at a constant rate which will be attractive to bed bugs. Thus it has been observed by the present inventors that there are optimal concentrations of such chemical attractants in terms of luring bed bugs to traps. Too low a concentration will be insufficient to attract bed bugs; conversely, at too high of a concentration, such “attractants” were found to have a repellent effect. Accordingly, in order for a bed bug monitor to be effective, it is necessary that such monitor release attractants at a desired rate for a substantial period of time, frequently for a week or more.
For several of the most effective bed bug attractants, including pheromones such as hexenal and octenal, and human sweat components such as butyric acid, it has been found that a very low rate of diffusion is optimal for attracting bedbugs. Specifically, in order to be most attractive to bedbugs, the optimal concentration of the Hexenal and Octenal mixture to be released is from about 50 ng/L/hr to about 200 ng/L/hour, and the optimal concentration of butyric acid to be released is between about 15 ng/L/hr and about 50 ng/L/hr. However, in order to avoid decomposition issues, such attractants are typically formulated in volatile organic solvents such as C8-C12 alkanes. Unfortunately, such solvents are so volatile that when exposed to air they quickly evaporate, resulting in a too-high initial release rate of attractants (which may in fact repel bed bugs). Further, this rapid release may quickly deplete the attractants from the monitor, with the result that after such high initial burst, the release rate is too low to effectively attract bed bugs.
Accordingly, there is a need for a means to release such attractants at a steady predetermined rate for an extended period of time.
In addition to the bed bug attractants discussed above, there is a similar need for the sustained, measured release of other materials including perfumes, air fresheners, aroma therapy components, pesticides, repellants and pharmaceuticals.